Electronic apparatus and waterproof structure therefor
View Patent ↗A waterproof structure for an electronic apparatus of the present invention includes keybuttons positioned such that their ends appear via holes formed in the casing of the apparatus. A circuit board is loaded with switches configured to selectively open or close when the keybuttons associated therewith are operated. A sheet member is formed of an elastic material and intervenes between the keybuttons and the circuit board. The sheet member includes, at least in its peripheral portion thereof, a seal portion for preventing water or similar liquid from entering the apparatus and reaching the surface of the circuit board. When the sheet member is pressed between the casing and the circuit board, the seal portion is at least partly pressed against the inside surface of the casing while being subject to a bending load.
1. A waterproof structure for an electronic apparatus comprising:
an operating member positioned such that an end of said operating member appears via a hole formed in a casing of said electronic apparatus;
a circuit board loaded with a switch configured to selectively open or close when said operating member is operated; and
a sheet member formed of an elastic material and intervening between said operating member and said circuit board;
said sheet member comprising, at least in a peripheral portion thereof, a seal portion configured to prevent a liquid from entering said electronic apparatus and reaching a surface of said circuit board;
wherein when said sheet member is pressed between said casing and said circuit board, said seal portion is at least partly pressed against an inside surface of said casing while being subject to a bending load.
2. The structure as claimed in claim 1 , wherein said operating member comprises a keybutton configured to cause the switch to selectively open or close said switch when pressed.
3. The structure as claimed in claim 1 , wherein when said sheet member is pressed between said casing and said circuit board, said seal portion bends and remains in a bent position with an end of said seal portion being pressed against the inside surface of said casing.
4. The structure as claimed in claim 3 , wherein when said sheet member is pressed between said casing and said circuit board, said seal portion bends with the end thereof sliding on the inside surface of said casing and is held in a position in which said seal portion exerts a restoring force.
5. The structure as claimed in claim 3 , wherein a root portion of said seal portion is reduced in thickness.
6. The structure as claimed in claim 5 , wherein a thickness of the root portion is selected in accordance with a force necessary for causing said seal portion to bend and the restoring force for hermetic sealing.
7. The structure as claimed in claim 3 , wherein the end of said seal portion has a semicircular section.
8. The structure as claimed in claim 3 , wherein the inside surface of said casing is formed of a material having a relatively small coefficient friction relative to a material that forms at least the end of said seal portion.
9. The structure as claimed in claim 3 , wherein a length of said seal portion is selected in accordance with an estimated dimensional error of at least one of said circuit board and said sheet member.
10. The structure as claimed in claim 3 , wherein said operating member comprises a plurality of operating members arranged in a preselected pattern,
said seal portion is configured to surround an area where said plurality of operating members are arranged,
said seal portion contacts the inside surface of said casing and includes a continuous seal region, which prevents the liquid from entering said electronic apparatus and reaching said circuit board, surrounding said area.
11. The structure as claimed in claim 3 , wherein said operating member is positioned on said sheet member.
12. The structure as claimed in claim 3 , wherein said operating member and said sheet member are formed of an elastic material integrally with each other.
13. In an electronic apparatus provided with a waterproof structure, said waterproof structure comprising:
an operating member positioned such that an end of said operating member appears via a hole formed in a casing of said electronic apparatus;
a circuit board loaded with a switch configured to selectively open or close when said operating member is operated; and
sheet member formed of an elastic material and intervening between said operating member and said circuit board;
said sheet member comprising, at least in a peripheral portion thereof, a seal portion configured to prevent a liquid from entering said electronic apparatus and reaching a surface of said circuit board;
wherein when said sheet member is pressed between said casing and said circuit board, said seal portion is at least partly pressed against an inside surface of said casing while being subject to a bending load.
14. The structure as claimed in claim 13 , wherein said operating member comprises a keybutton configured to cause the switch to selectively open or close said switch when pressed.
15. The structure as claimed in claim 13 , wherein when said sheet member is pressed between said casing and said circuit board, said seal portion bends and remains in a bent position with an end of said seal portion being pressed against the inside surface of said casing.
16. The structure as claimed in claim 15 , wherein when said sheet member is pressed between said casing and said circuit board, said seal portion bends with the end thereof sliding on the inside surface of said casing and is held in a position in which said seal portion exerts a restoring force.
17. The structure as claimed in claim 15 , wherein a root portion of said seal portion is reduced in thickness.
18. The structure as claimed in claim 17 , wherein a thickness of the root portion is selected in accordance with a force necessary for causing said seal portion to bend and the restoring force for hermetic sealing.
19. The structure as claimed in claim 15 , wherein the end of said seal portion has a semicircular section.
20. The structure as claimed in claim 15 , wherein the inside surface of said casing is formed of a material having a relatively small coefficient friction relative to a material that forms at least the end of said seal portion.
21. The structure as claimed in claim 15 , wherein a length of said seal portion is selected in accordance with an estimated dimensional error of at least one of said circuit board and said sheet member.
22. The structure as claimed in claim 15 , wherein said operating member comprises a plurality of operating members arranged in a preselected pattern,
said seal portion is configured to surround an area where said plurality of operating members are arranged,
said seal portion contacts the inside surface of said casing and includes a continuous seal region, which prevents the liquid from entering said electronic apparatus and reaching said circuit board, surrounding said area.
23. The structure as claimed in claim 15 , wherein said operating member is positioned on said sheet member.
24. The structure as claimed in claim 15 , wherein said operating member and said sheet member are formed of an elastic material integrally with each other.